The present invention relates as indicated to an air suspension seat assembly for use in vehicles, such as trucks and buses.
In the past, pneumatic spring supporting systems have been employed to absorb the shock and vibratory loads encountered in normal use of such vehicles. Conventionally, the opposed ends of the fluid spring were respectively directly connected to the vehicle floor and seat frame whereby the vertical adjustability of the seat was limited to the vertical adjustability of the fluid spring itself. In such systems, the seat assemblies were often rather extensive in height because of the rather extensive vertical dimension of the fluid spring support assemblies, whereby the use thereof was often limited because of head room restrictions in the vehicle cab.
To alleviate some of the above-noted problems, Dome U.S. Pat. No. 3,298,654, assigned to the predecessor in interest of the assignee of the present application, disclosed and claimed a vehicle seat support having a vertically movable base frame beneath the seat cooperating with the fluid spring to provide vertical adjustment of the seat a distance substantially in excess of the vertical adjustability of the fluid spring itself. Such vehicle seat support eliminated many of the problems inherent in the earlier fluid supporting systems and has long been satisfactorily commercially used.
However, the placement of the seat support structure beneath the seat itself, even with the noted increased seat travel characteristics of the Dome patented structure, requires a certain degree of vertical clearance that is often times not present in the limited volume vehicle cabs. Moreover, the subjacent base frame assembly does not have sufficient rigidity to withstand the seat belt loading requirements set by the Department of Transportation, which thus requires tether straps connected to the vehicle to be used for compliance. The base support structure also adds to the overall weight of the vehicle seat. Finally, the distance from the passenger's center of gravity when seated to the mounting location at the bottom of the base support causes relatively high side to side inertial thrusts during use resulting in suspension wear and thus some transverse looseness in the frame.
With the above in mind, the seat assembly of the present invention minimizes the rough ride of a vehicle by using the principles of air suspension seats shown in the Dome patent, while improving certain structural and functional aspects of the subjacent base support structure shown in such patent. Specifically, the primary object of the present invention is to provide an air suspension system for a seat with such air suspension system being located behind the seat back.
Another object of the invention is to provide a light-weight seat contained within a very limited space both horizontally and vertically.
It is still another object of the present invention to provide an air suspension seat assembly that substantially eliminates side to side or transverse looseness.
These and other objects and advantages of the present invention will become apparent as the following description proceeds.
To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.